Underwater wall mounted pool lights have long since been a standard feature in swimming pools.
Known pool lights are commonly sold with a power cable sealingly secured into the housing of the light fitting. The cable is connected to a power source and installed in a semi-permanent manner between the electricity supply connection and the desired point of installation. The cable is also typically coiled into a recess in the wall at the point of installation to allow the light fitting to be moved between an underwater mounted position and a position above the level of the water.
To replace a light fitting the existing cable installation is usually left intact. This applies where the cable is fixed semi-permanently between the power source and the installation point. The alternative of replacing an existing, laid cable with a new one is too difficult and impractical.
The replacement thus requires cutting the existing cable at the old light fitting, cutting the bulk of the new light fitting cable off, stripping the free ends of both cables and joining them in a sealed manner so that water does not come into contact with the cable wires. This method is not desirable for its lack of elegance and reliability.